actinium

[ ak-tin-ee-uhm ]

/ ækˈtɪn i əm /

noun Chemistry.

a radioactive silver-white metallic element that glows blue in the dark, resembling the rare earths in chemical behavior and valence. Symbol: Ac; atomic number: 89; atomic weight: 227.

Origin of actinium

First recorded in 1900–05; actin- + -ium

Words nearby actinium

actinide, actinide series, actiniform, actinin, actinism, actinium, actinium series, actino-, actinobacillosis, actinobacillus, actinobiology

Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Example sentences from the Web for actinium

For if actinium was an independent element we would be sure to find actinium haloes.
The Birth-Time of the World and Other Scientific Essays|J. (John) Joly
Actinium, an element or elementary substance obtained in minute quantities in connection with the study of radioactivity.
The New Gresham Encyclopedia. Vol. 1 Part 1|Various
These are generally known as radium emanation, thorium emanation, and actinium emanation.
A Brief Account of Radio-activity|Francis Preston Venable
In this class are now placed also the three radio-active gases, emanating respectively from radium, thorium, and actinium.
A Brief Account of Radio-activity|Francis Preston Venable

Emanium was the name originally proposed by Giesel for the body now known as actinium.
A Brief Account of Radio-activity|Francis Preston Venable

British Dictionary definitions for actinium

actinium

/ (ækˈtɪnɪəm) /

noun

a radioactive element of the actinide series, occurring as a decay product of uranium. It is used as an alpha-particle source and in neutron production. Symbol: Ac; atomic no: 89; half-life of most stable isotope, 227 Ac: 21.6 years; relative density: 10.07; melting pt: 1051°C; boiling pt: 3200 ± 300°C

Word Origin for actinium

C19: New Latin, from actino- + -ium

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for actinium

actinium

[ ăk-tĭn′ē-əm ]

n. Symbol Ac

A radioactive element found in uranium ores. Its longest lived isotope is Ac 227 with a half-life of 21.6 years. Atomic number 89.

Scientific definitions for actinium

actinium

[ ăk-tĭn′ē-əm ]

Ac

A silvery-white, highly radioactive metallic element of the actinide series that is found in uranium ores. It is about 150 times more radioactive than radium and is used as a source of alpha rays and neutrons. Its most stable isotope has a half-life of about 22 years. Atomic number 89; melting point 1,050°C (1,922°F); boiling point (estimated) 3,200°C (5,792°F); specific gravity (calculated) 10.07; valence 3. See Periodic Table.

单词	actinium
释义	actinium [ ak-tin-ee-uhm ] / ækˈtɪn i əm / noun Chemistry. a radioactive silver-white metallic element that glows blue in the dark, resembling the rare earths in chemical behavior and valence. Symbol: Ac; atomic number: 89; atomic weight: 227. Origin of actinium First recorded in 1900–05; actin- + -ium Words nearby actinium actinide, actinide series, actiniform, actinin, actinism, actinium, actinium series, actino-, actinobacillosis, actinobacillus, actinobiology Dictionary.com UnabridgedBased on the Random House Unabridged Dictionary, © Random House, Inc. 2020 Example sentences from the Web for actinium For if actinium was an independent element we would be sure to find actinium haloes. The Birth-Time of the World and Other Scientific Essays\|J. (John) Joly Actinium, an element or elementary substance obtained in minute quantities in connection with the study of radioactivity. The New Gresham Encyclopedia. Vol. 1 Part 1\|Various These are generally known as radium emanation, thorium emanation, and actinium emanation. A Brief Account of Radio-activity\|Francis Preston Venable In this class are now placed also the three radio-active gases, emanating respectively from radium, thorium, and actinium. A Brief Account of Radio-activity\|Francis Preston Venable Emanium was the name originally proposed by Giesel for the body now known as actinium. A Brief Account of Radio-activity\|Francis Preston Venable British Dictionary definitions for actinium actinium / (ækˈtɪnɪəm) / noun a radioactive element of the actinide series, occurring as a decay product of uranium. It is used as an alpha-particle source and in neutron production. Symbol: Ac; atomic no: 89; half-life of most stable isotope, 227 Ac: 21.6 years; relative density: 10.07; melting pt: 1051°C; boiling pt: 3200 ± 300°C Word Origin for actinium C19: New Latin, from actino- + -ium Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Medical definitions for actinium actinium [ ăk-tĭn′ē-əm ] n. Symbol Ac A radioactive element found in uranium ores. Its longest lived isotope is Ac 227 with a half-life of 21.6 years. Atomic number 89. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company. Scientific definitions for actinium actinium [ ăk-tĭn′ē-əm ] Ac A silvery-white, highly radioactive metallic element of the actinide series that is found in uranium ores. It is about 150 times more radioactive than radium and is used as a source of alpha rays and neutrons. Its most stable isotope has a half-life of about 22 years. Atomic number 89; melting point 1,050°C (1,922°F); boiling point (estimated) 3,200°C (5,792°F); specific gravity (calculated) 10.07; valence 3. See Periodic Table. The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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